Optiphone



F. C. BROWN.

OPTIPHONE- APPLICATION FILED JULY 31,1916.

1,852,940. v PatentedSept. '14, 1920;

FAY c. aown, or BERKELEY, cALIEo NIA.

OPTIPHONE.

Specification of Letters Patent.

Continuation of application Serial No. 26,357, filed May 6, 1915 Thisapplication filed Ju1y 31, 1916.

Serial No. 112,294. v A

To all whom it may concern:

Be it known that I, FAY C. BROWN, a citizen of the United States,residing at Berkeley, in the county of Alameda and State of California,have invented certain new and useful Improvements in .Optiphones, ofwhich the following is a full, clear, concise, and exact description.

This invention has reference to optiphones; that is, an instrumentwhereby an appreciation of the shape or certain characteristics of anobject, due to the effect of light either emitted thereby or reflectedtherefrom or transmitted therethrough, may be obtained through the senseof hearing. One application of this is that a person who isblind ornearly so may be enabled to see by the aid of the ear, or may beenabledto obtain some appreciation -of the eflect obtained through vision.

The present invention in its preferred form is based'upon an electricalcharacteristic of metallic selenium, inthat light causes a reduction inthe electrical resistance of selenium. It is not, however, limited tothe use of selenium, as other light sensitive substances or devices maybe employed.

In the present invention when selenium is employed advantage is taken ofthe improved response -of selenium to light when the selenium is underpressure, and, moreover, the furtherimprovement in the responsiveness tolight when the selenium is employed in relatively large crystals,'commonly distinguished as large by the term macroscopic crystals eithersingle.crystals or groups thereof. Advantage is also taken of the factthat with individual crystals of selenium used as bridges light raysfrom a definite portion of an ObJGCt may be focused upon the seleniumcrystal with any de cc of exactness desired. 1

he present invention contemplates the employment of an association ofselenium crystals in different circuits, each of which,

is so arran ed as to have a diiferent tone characteristic from theothers, and the group By this-means a letter of the selenium cells orcrystals, each included in an electric circuit characteristic thereto,will affect the group of selenium crystals -in a.

made up of the group of associated selenium crystals controllingcorresponding electric circuits. Such circuits must, of course, becharged circuits and each clrcuit 1s made Patented se t. 14, 1920.

to produce a'sound characteristic of it by f any suitable means, as byan interrupter producing a characteristic tone, or by taking advantageof the effect of resonance, or otherwise, so that considering the letterto be observed as a white or light-letter, the

observer hears by means of instruments,

such as telephones, a series of tones locat-' ing the altitude withrelation to some basic oint of the difierent parts of the letter. ysuchmeans the healer may readily learn to appreciate the shape of the lettersimilarly as a blind person is enabled to appreciate the shape of aletter by the sense of touch. Such an instrument enables a blind personto read print with considerable rapidity and to gain an appreciation ofthe,

shape and intensity of illumination by a source of light or theintensity of reflectiontherefrom. The general'idea of the opti-.

phone, as herein described, is'not new, bemg described, for example, inan articleentltled The optophone in the English Mechanic and World ofScience, page 481, volume 95,

and an article entitled The differential optiphone .in the EnglishMechanic and World of Science, page 75, volume 96. This invention hasfor its objects, the provision of certain improvements in such devices,the particular improved means being described herein and pointed out inthe ap pended claims.

' The preferred form of the invention will be best understood from aconsideration of the following detailed description, taken in connectionwith the accompanying drawings'forming a' part of this specification,with the further understanding that while the drawings show a practicalform of the invention, the latter is not confined to any 7 strictconformity with the showing of the drawings, but may be changed andmodified so long as such changes and modifica tions make no materialdeparture from the salient features of the invention.

In the drawings Figure 1 is a diagram illustrating the optiphone. Fig. 2is a diagram'illustrating a multitelephone receiver useful in connectionwith an instrument constructed in accordance with the showing of Fig. 1.s

Fig. 3 is a diagram illustrating a modified form of optiphone.

Referring to the drawings there. is shown at 1 representations ofcrystals of selenium without any attempt to show the actual formsthereof. These crystals are each in bridging relation to contacts 2, 3and either or both of said contacts is capable of movement to exertpressure upon the crystal 1. In the drawings the contact 2 is shown asunder the control of a screw 4 by means of which the. contact may bepressed into engagementwith the crystal 1 and the latter forced againstthe contact 3, so that any desired degree of pressure may be exertedupon the crystal.

Several crystals-1 are grouped together in close relation so as to formwhat may be termed a screen. Associated with the selenium screen is alens 5 so arranged as to focus the object to be observed upon theselenium screen. The lens 5 typifies any suitable arrangement offocusing and reflecting means for directing rays from a definite portionof an object upon the selenium crystals. Selenium resistances haveheretofore been used which consisted of a heterogeneous mass of seleniumupon which light could not be accurately focused be- 40 cause they hadsensitive and insensitive portions and were very uncertain in their action. By the use of lenses for focusing the light upon bridgesconsisting of a smgle definite crystal, smaller objects may be scannedwith greater accuracy and speed pair of contacts2 and 3 may beconsidered than has been possible with arrangements used heretofore. Inthe drawings such object is represented by a letter 6.

A selenium crystal or crystals 1 with a as a selenium cell, and onecontact of each cell, say, the contact 2, is connected by a conductor 7individual thereto, to one side of a variable resistance 8. The otherterminals of the'resistances 8 are all connected together at a commonpoint indicated at 9 and to this common point is connected one side ofbattery 10 which may be taken as representative of any suitable sourceof electrical current, which, in the diagram of Fig.- 1, may be directcurrent.

The other side of each selenium cell has the contact 3 connected to acommon conductor 11, which in turn is connected to the other side of thebattery 10.

Also connected to the opposite terminals of the battery 10 is a branchedcircuit including in series with each other the fixed.

- other side of each telephone receiver is connected by a conductor '22to a respective conductor 7.

It will be seen that the arrangement thus far described constitutes aplurality of Wheatstones bridges ,or networks in which the four arms ofany one bridge consist of one selenium cell 1, the correspondingresistance 8, and the resistances 12 and 13. The expression Wheatstonebridge? will, for the purposes of this specification, be understood todefine a network of any nature having a branch included therein andcapable of such adjustment that the said branch will be conjugatewithrespect to another branch. The corresponding interrupter 18, andtelephone 21, and the battery 10, are connected in the usual manner fora Wheatstone bridge, andthis bridge or network may then be balanced forthe desired condition by varying the resistance 8. The remainingnetworks are similar in every respect to the one thus described. It isapparent that each selenium cell may be in a Wheatstone network, whichis entirely independent and separate from each other network, butinasmuch as the necessary balancing of any one network may beaccomplished by the adjustment of the arm 8 alone, it-is possible andconvenient to combine the networks in such a manner as shown in'thedrawing and disclosed above, in which case the resistance arms 12 and13, and the battery 10 are common to sounds produced by a relativelylarge number of telephone receivers covering a considerable extent ofsurface represented by the grouping of the selenium cells or crystals 1.This novel form of receiver, whlch is especially adapted for use inoptiphones, constitutes one improvement therein'which is hereinafterclaimed.

It may be assumed that the selenium The resistances 8' are properlyadjusted so that each l/Vheatstones bridge is balanced and no currentflows through the telephones 21 and they are, accordingly, silent.

Suppose, now, that the image of the letter represented at 6, whichrepresentation is of the letter A, be caused to move over the seleniumscreen, and let it be further assumed that the letter is a white letterupon a black or dark background. Considering the letter as seen in thedrawing and moving from right to left, which is in opposition to thereading movement of the eyes, the lower left hand corner of the letterwill first engage the selenium screen, thus affecting the correspondingone or more of the selenium crystals 1 and destroying the bridge balanceand causing the corresponding telephone to respond.

When theeffect of the passing letter or character is present upon theselenium screen. made up of separate crystals or groups of crystals inseparate circuits, the progress of the image of the letter across thescreen is made known to the listener by successive.

characteristic sounds or hums due to the action of the differentinterrupters 18 or other means of producing impulses at audible rates,and these characteristic sounds impart to the listener correspondingimpressions which, the listener has learned,'have to do with differentpositions, so that the general impression on the ear of the listener issimilar to the impression of the character upon the eye of one capableof seeing. It is because of thisvariation of impression upon the earthat those unable to see may, by the aid of the invention,understandingly read printed matter or gain a correct idea of the shapeand other characteristics of an object which, when illuminated, aflectsthe instrument of the present invention in the manner described.

While it is possible, as suggested above, to use white letters on ablack back-ground, it is in practice desirable to reverse this, and useblack letters on a white back-ground in conformity with usual practicein printing. In this case the various telephones are brought to silenceby adjustment of resistance 8, when the crystals are illuminated bylight reflected from the plain/white background. When a portion of a.black letter is brought into the field'of the screen, the

intensity of light,reflected from that'por-- It is obvious, of course,that the adjust ment of the circuits may be such that normally one ormore of the telephonesis emitting its characteristic tone with a certainintensity, which intensity may be either in creased or decreased whenthe image comes within the field.

While the source of current-1O has been shown as a direct currentsource, which is interrupted by some suitable form of interrupter, it isto be understood that such source may be replaced by a source ofalternating current of any desired frequency as shown in Fig. 3. Such anarrangement is suitable either in case the various VVheatstone bridgesor networks are independent and separate, or in case a telephonereceiver of the type shown in Fig. 2 and common to all or a plurality ofthe bridges is employed.

The present invention in the preferred form contemplates the use ofrelatively large selenium crystals which are free from complexitiesfound in amorphous selenium and the greatly increased conductivity ofsele- Y nium under light when the selenium crys tal is subjected topressure.

. lVhile the present invention is designed more particularly forenabling those unable to see to obtain'intelligible impressions by theaid of hearing corresponding to the impressions obtained by sight, somefeatures of the invention are capable of wider use, these featuresincluding the employment of single selenium crystals of large size andthe employment of. such crystals under-presferent circuits at audiblerates and of different characteristics from each other, telephonicreceiving means lndlvidual to each I circuit for translating theelectrical impulses I into audible sounds, and a common earpiece forsaid receiving means.

2. An optiphone comprising a plurality of circuits each having meanstherein for producing'electrical impulses differing in character fromthose of the other circuits and at audible rates, separate telephonictranslating means for the electrical impulses, a common means forapplying said translating means to-the ear, and a resistance included ineach of the circuits and individual thereto with the resistances groupedinto close association to individually and collectively receivecorresponding parts of a light image directed upon the group ofresistances.

3'. An optiphone comprising a group of Wheatstone network's or bridges,each including a'resistance element as one arm, and

' means for balancing said bridges, an electromagnetic receiver as anindicator in each bridge, a common casing for saidreceivers, and anaudio frequency interruptor in series with each telephone, incombination W ithmeans for'focusi-ng on the respective resistancescertain portions of an image.

4:. In an optiphone, the combination of a selenium bridge comprising asingle crystal of selenium and a lens for focusing an image upon saidcrystal.

' 5. An optiphone comprising a plurality of circuits, and means in eachcircuit for producing impulses differing-in character from those of theother circuits and at audible rates, telephonic translating means forthe electrical impulses, a resistance in each of said'circuits, saidresistances each comprisdividually different characteristics, and atelephone receiver in each circult.

,7. An optiphone comprising a group of \Vheatstone bridges, eachincluding a macro- 8. An optiphone comprising means for the electricalproduction of sounds of defi-j nite characteristics, and separateresistance, devices individual to the different means in-f cluded incircuit therewith to control such means by the action of light upon theresistance devices, said resistances being associated in linear relationso that when passed before a series of characters of the kind used inprinting or writing they will be affected differently and in a mannercharacteristic of the individual characters.

9. An optiphone comprising a plurality of light sensitive elements,individual means responsive to each of said elements to' produce adistinct effect in accordance with the light falling upon the respectiveelement, and a common receiver connected to each of said individualmeans to blend said distinct effects into a composite audible effect.

I In witness whereof, I hereunto subscribe my name this twentieth dayofJuly, A. D.

FAY C. BROWN.

